Totipotent Stem Cells

Definition: These are the most versatile stem cells, capable of developing into any cell type in the entire organism, including both embryonic and extra-embryonic tissues.

Examples: The zygote and early embryonic cells (up to the 8-cell stage) are totipotent.

Differentiates Into:

• Every type of cell in the body, as well as extra-embryonic tissues such as the placenta.

Pluripotent Stem Cells

Definition: These cells can differentiate into almost any cell type but are limited to the cells of the three germ layers: ectoderm, mesoderm, and endoderm. They cannot form extra-embryonic tissues like the placenta.

Examples: Embryonic stem cells (ESCs) derived from the inner cell mass of the blastocyst.

Differentiates Into:

• Ectoderm: Forms skin cells, neurons, and other neural tissues.
• Mesoderm: Forms muscle cells, bone cells, blood cells, and other connective tissues.
• Endoderm: Forms cells of the gastrointestinal tract, lungs, and other internal organs.

Multipotent Stem Cells

Definition: These stem cells can differentiate into multiple cell types, but their potential is more limited compared to pluripotent stem cells. They can produce cells of a specific lineage or related family of cells.

Examples:

• • Hematopoietic Stem Cells (HSCs): Found in bone marrow and can differentiate into all types of blood cells (e.g., red blood cells, white blood cells, platelets).
  • Mesenchymal Stem Cells (MSCs): Found in bone marrow, adipose tissue, and other tissues, and can differentiate into bone cells, cartilage cells, and fat cells.
  • Neural Stem Cells (NSCs): Found in the brain and can differentiate into various types of neural cells (e.g., neurons, astrocytes, oligodendrocytes).

Differentiates Into:

• HSCs: Different types of blood cells.
• MSCs: Bone, cartilage, and fat cells.
• NSCs: Different neural cells like neurons and glial cells.